Locomotive boiler construction



J. A. M GREW LOGOMOTIVE BOILER CONSTRUCTION July 18, 1933. i

2 Sheets-Sheet 1 Filed D90. 7, 1931 July 18, 1933. J. A. MCGREW 1,918,655

LOCOMOTIVE BOILER CONSTRUCTION Filed Dec. 7, 1931 2 Sheets-Sheet 2 "Patented July 18, 1933 PATENT OFFICE JOHN A. ICGREW, OI LLB ANY, NEW YORK LOCOMOTIVE BOILER .CONSTBUCTION Application filed December I, 1881;

The present invention relates to locomotive boiler constructions and particularly to steamsuperheaters designed and constructed to impart a high degree of heat to the steam supplied to the locomotive cylinders and auxiliary appliances.

The many advantages of superheating the steam introduced into the cylinders of locomotives are welLknown, and the great majority of locomotives now in use embod superheaters. While many types of super eaters have been heretofore designed or suggested, there are only two types of such devices in use, and these differ only slightly in design and construction.

Thus, the generally accepted type of superheater comprises a rather complicated header positioned within the locomotive boiler shell in advance of the forward tube sheet, and proj ecting rearwardly from this header and into the fire tubes of the boiler are a plurality of steam conduits of small diameter which conduct steam from the header rearwardly through the several tubes toward the firebox and thence again forwardly to the header. From the header the steam is withdrawn and passed to the engine cylinders. A superheater of this type comprises a large number of parts, making it costly to construct and cumbersome to install. Furthermore, frequent inspections must be made and from time to time expensive replacements of parts effected. Again, the various superheater tubes, extending as they do into the fire tubes of the boiler, tend to-impede the free passage, through the fire tubes, of the products of combustion from the firebox.

, The present invention contemplates an improved superheater for locomotive boiler constructions by means of which a very high degree of superheat may be imparted to the steam supplied for propulsion purposes but which, at the same time, is of very sim le de sign, containing a minimum number 0 parts which are rugged and durable, thus promoting economy by reason of lower first cost and lower cost of inspection and maintenance.

A feature of the improved superheater construction consists'in its ability to serve both as superheater and firebox arch. In practi- Berial No. 578,883.

cally all types of locomotives, firebox arches are employed to deflect rearwardly, or baflle, the products of combustion arising from the fuel on the forward part of the firebox in order that'these gases may have full opportunity to burn before entering the fire tubes and passing to the smoke box. A more complete combustion of the fuel and decreased amount of objectionable smoke results. In accordance with the present invention, the superheater is so formed and is so positioned and supported within the firebox that it comprises a very satisfactory type of firebox arch, which arch is superior to and less expensive 'to install and operate than firebox arches of the type heretofore in general use. The superheater is supported in the firebox in a novel manner so that no strain is imposed upon ltby reason of the expansion and contraction ofits walls and the walls of the firebox due to changes in temperature.

I In the accompanying drawings, one form of the invention is illustrated. Those skilled in the art will appreciate, however, that, in adapting the principles of the invention to locomotive or other boilers which differ in size and details of construction and arrangement of parts, the design and arrangement of the various elements of the invention may be considerably modified, that form of the invention illustrated being set forth by way of example only.

In the drawings:

Figure 1 is a vertical axial section through a locomotive type of boiler construction showing the superheater positioned in the'firebox thereof;

Figure 2 is a top plan view of the same partially broken away;

Figure 3 is a section on line 3-3 of Figure 1; and

Figure 4 is a section on line 44 of Figure 1. I

The shell of the boiler construction is generally indicated at 10, the firebox space at 11, the smoke box at 12, and the water space at 13, it being understood that that portion of the boiler interior above the water level comprises the steam space. The steam dome is indicated at 14. The firebox walls 17 its sides.

11 is substantially rectangular in horizontal section, the rear tube sheet 15 constituting its forward wall, the crown sheet 16 its top, and the downwardly and outwardly inclined The forward tube sheet is indicated at 18, and assing through the transversely disposed tu sheets 15 and 18 and connecting the firebox 11 and the smoke box 12 are a plurality of fire tubes 19, through which the spent products of combustion from the fuel in the firebox pass in a forward direction to be ultimately discharged from the stack 20. Forward and rear throat sheets are indicated at 21 and 22 respectively, both sheets being vertically disposed and sheet 22 being connected to the rear tube sheet 15, a rearwardly projecting flange of the tube sheet being secured to a forwardly projecting flange of the rear 50 throat sheet, a shoulder, indicated at 23, being thus formed at the base of the rear tube sheet.

The superheater is generally indicated at S and comprises essentially a sin le tortuous conduit'formed preferably 0 pipe of rather large diameter, which conduit comprises a plurality of straight sections connected by bends 31, the straight sections lying parallel and closely adjacent to one another and also in a common plane inclined to the horizontal and to the tube sheet 15 so that the superheater unit as an entirety is inclined as shown in Figure 1 and occupies the position which is normally occupied by the rebox arch. The up er ends of the outer straight sections 30 o the superheater are connected by inclined ipe sections 32 and 33, respectively, with orwardl extending conduits 34 and 35 of substantia y the same diameter as the pipes or conduits which comprise the superheater unit.

Conduits 34 and 35 are positioned centrally'in enlarged fire tubes 36 and 37 a space annular in cross section bein left between the outer walls of the con nits and the inner walls of the tubes for the passage of hot products of combustion. Conduit 35 constitutes a means for conducting saturated steam to the superheater, being connected by a laterally extending conduit 38 to the usual dry pipe 39 of the boiler. Conduit 34 comprises the superheater exhaust ipe or the means for conducting the big ly superheated steam from the su erheater to a front end throttle, such as in icated at 40. This throttle may be of any suitable type, such, for instance, as that known as the Bradford front end superheated steam throttle, and controls the flow of superheated steam to the engine cylinders through pipes 41 and 42 respectively, the cylinders having been omitted I from the drawin s for the sake of clarity.

Conduit 34 has a ateral and relatively small a branch 43 intermediate the superheater and vvalv e,"-1 by means of which a small proportion of the steam may be conducted away to auxiliaries. This pipe is normally open, even when throttle valve is closed, so that a certain flow of steam through the superheater occurs so long as the fire is maintained in the firebox.

The front end throttle 40 may be operated in various ways, but the linkage shown in Figures 1 and 2 is well suited for the mani ulation of this throttle from the engine cab, the operating lever or throttle lever being indicated at 45. The several parts of the linkage, including the sliding rods 46 and 47 with their connecting rocker 48, are mounted on the exterior wall of the boiler shell. A steam shut-oil valve, the details of which are not illustrated as they comprise no portion of the present invention, is indicated at 50, this valve being located in the steam dome and designed and constructed to entirely close the end of the dr pipe 39. It is operated by mechanism of well-known character including the rotatable rods 51 and 52 connected by a swivel joint 53, the handwheel shaft 54 connected by a joint 55 to rod 52, and the hand-wheel 56.

In the 0 eration of the boiler plant, steam will flow rom the steam dome 14 through the series of tubes just described in the direction of the arrows, the steam being changed in its passage from its saturated state to a very highly superheated state and thence passing to the engine c linders when the throttle valve 40 is opene The superheater unit S, being disposed directly above the fire and exposed to the highest temperatures which exist in the firebox above the fuel bed, is highly heated and brings the steam passing therethrough to a high degree of superheat. The heating is continued during the passage of the superheated steam through the fire tube 36, little of its contained heat, if any, being lost in its passage through the throttle valve and downtakes 41 and 42. Steam passing rearwardly through conduit 35 to the superheater is likewise given some degree of superheat before it reaches the superheater.

Interiorly the pipe or conduit from which the superheater unit S is built up is preferably provided with a series of webs such as shown in Figure 4. These webs serve to rapidly conduct heat from the walls of the superheater tube to the interior thereof so that all portions of the a'seous stream passing therethrough are efi actively heated, this rapid heat transfer likewise tending to prevent dangerous overheating of the superheater during the operation of the locomotive.

The various strai ht sections of the superheater unit S may slightly spaced apart as shown in the drawings, or their adjacent elements may be connected as by welding, or refractory material may be placed so as to lob fill the pa between the adjacent surfaces of the tu to prevent the passage of products of combustion from the fuel bed directly through the superheater unit'to tubes 19. Likewise closures for the spaces intermediate the outside sections of the superheater and the side walls 17 of the firebox may be provided, each suchclosure referably comprising a plurality of brick-like refractory memrs having their lower ends restin against the outer tubes of the superheater and their u per ends against the side walls of the fire x. These refractory closures prevent passa e of products of combustion from the fuel upwardly around the sides of the superheater.

The superheater is preferably supported in the position in which it is shown b means of a bracket 61 positioned centrall t ereof and secured to the central lower bracket projecting over and resting upon a member 62 whic in turn rests upon the shoulder 23 formed at the foot of the rear tube sheet. By means of the bracket, a large proportion of the wei ht of the superheater is transmitted to the conduits 34 and 35-heretofore described constitute the means for maintaining the superheater unit in its inclined position, these conduits serving to tie the upper portion of the superheater to the forward, portion of the boiler structure. By a construction of this kind, in which the su erheater unit is not rigidly braced to portions of the firebox, it may rock very slightly about the point of support at its base as the various metallic parts of the locomotive boiler expand and contract due to changes in temperature. This is a very material advantage in connection with a structure of this kind, and the entire superheater assembl is relieved of any excessive strains to w ich it might otherwise be subjected by reason of temperature changes and expansion of its parts as well as changes in dimension of the boiler structure itself. I

In accordance with the present invention also, the locomotive safet valve is located in a novel position u n t e boiler structure. This safety valve is indicated at V in the drawings and is located preferably near the front end throttle 40. At all events it is positioned between the superheater unitand the throttle valve, that is, so positioned that when it becomes operative, it discharges superheated steam into the atmos here. Heretofore such safety valves have en positioned to discharge saturated steam, when open. By locating the safety valve in such position that it discharges superheated steam, the superheater itself is provided with an increased measure of rotection against overheating. Thus'the' sa ety valve is most likely to be called into operation when the locomotive is at a stop, or when drifting with closed nd 31, this iler structure. The

throttle, at which times excessive steam pressure is most likely to be developed within the boiler. With the'throttle closed, the superheater unit is most likely to be overheated as the flow of steam therethrough is interrupted and the cooling effect of the steam greatly reneed not be perfectly fiat but may assume anyconfiguration, in either a transverse .or a longitudinal direction, which is found in the usual firebrick locomotive arch construction. Thus, when it is stated in certain of the subjoined claims thatthe convolutions of the.

superheater unit are disposed in a plane making an angle with the rear tube sheet, the plane referred to is not necessarily "a strictly mathematical plane, but this terminology s I intended to embrace equivalent designs in which the unit may be curved or arched slightlyin either direction in simulation of the accepted firebrick arch construction.

It is also understood that various other changes and modifications in the embodiment 1 illustrated and described may be made with out departing from the sco of the invention as defined in the following claims.

, Having thus described the invention, what is claime as new and desired to be secured by Letters Patent is 1- a 1. A locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets disposed transversel of the shell and tubes for products of com ustion-passing through the said sheets and intermediate waters ace, and a superheater positioned in the fire x and designed and constructed to likewise constitute a firebox arch, said superheater comprising a tortuous steam conduit, the convolutions thereof being disposed in a plane making an angle with the rear tube sheet, and the lower edge of the arch being closely adjacent the rear tube sheet and the lateral edges adjacent the side walls of the firebox. P

2. A locomotive boiler construction comprisin a boiler shell having a firebox, spaced tube eets disposed transversel of the shell and tubes for products of com ustion passing through the said sheets and intermediate water space, and a superheater positioned in the firebox and desi ed and constructed to likewise constitute a rebox arch, said so rheater comprising a tortuous steam con uit fabricated of pipe of relatively large diam-- an angle with the rear tube sheet-,and the no lower edge of the arch bein closely adjacent the rear tube sheet and t e lateral edges closel adjacent the side walls of the firebox.

31 X locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets disposed transversely of the shell and tubes for products of combustion passing through the said sheets and intermediate water space, and a superheater positioned in the firebox and designed and constructed to likewise constitute a firebox arch, said superheater comprising a tortuous steam conduit, the

.convolutions thereof being disposed in a plane making an angle with the rear tube sheet, the lower edge of the arch being closely adjacent the rear tube sheet and the lateral edges ad acent the side walls of the firebox and refractory material filling the spaces between the lateral edges of the superheater and the side walls of the firebox.

4. A locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets extendingv transversely thereof and tubes for products of combustionpassing through said sheets and intermediate water s ace, and a superheater unit located in the firebox, said unit being supported at a single point upon the front wall of the firebox and also supported by means extending forwardly therefrom through one or more of said tubes and anchored to the boiler structure in advance of the forward tube sheet.

5. A locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets extending transversely thereof and tubes for products of combustion passing through said sheets and the intermediate water space, a superheater unit located in the firebox, and means for supporting the unit in inclined position, said means including a device for attachin the lower edge of the superheater to the irward wall of the firebox and elongated members passing through certain of the tubes for attaching the upper portion of the superheater for support to the boiler structure in advance of the forward tube sheet.

6Q A locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets extending transversely thereof and tubes for products of combustion passing through said sheets and the intermediate water space, a superheater unit located in the firebox and comprising also a firebox arch, and forwardly extending means for securing said superheater unit to said boiler shell at points forwardly of said unit in the properly inclined position to perform the arch function, said unit being otherwise unsu ported.

A locomotiveboiler construction com prisin a boiler shell having afirebox, spaced tube s eets extending transversely thereof and tubes for products of combustion passing through said sheets and the intermediate water space, a superheater unit located in the fire-box and comprising also a firebox'arch, and supporting means for said su erheater unit comprising steam inlet and ischarge pipes for the superheater extending for wagrdly thereof'through certain of the boiler tu es.

8. A locomotive superheater installation including, in combination, a combined firebox arch and superh ater unit comprising a metallic member providing a tortuous steam conduit and having its forward edge disposed in contact with the inner throat sheet of the firebox and extending upwardly and rearwardly therefrom, and steam conduits connecting said unit with the locomotive boiler and the engine cylinders respectively.

9. A locomotive superheater installation including, in combination, a combined firebox arch and superheater unit comprising a metalic member providing a tortuous steam conduit and having its'forward edge disposed closely adjacent the inner throat sheet of the firebox and extending upwardly and rearwardly therefrom, steam conduits connecting said unit with the locomotive boiler and the engine cylinders respectively, and means associated with the lower forward portion of one of said convolutions for supporting said unit from said inner throat sheet.

10. A locomotive superheater installation including, in combination, a combined firebox arch and superheater unit comprising a metallic member providing a tortuous steam conduit and having its forward edge disposed closely adjacent the inner throat sheet of the firebox and extending upwardly and rearwardly therefrom, steam-conduits connecting said unit with the locomotive boiler and the engine cylinders respectively, and a bracket secured to the lower forward portion of the central one of said convolutions and adapted to rest upon a cooperating bracket secured to said inner throat sheet.

11. A locomotive boiler construction comprising a. boiler shell having a firebox, spaced tube sheets disposed transversely of the shell and tubes for products of combustion passing through the said sheets and intermediate water space, a superheater positioned in the firebox and designed and constructed to likewise constitute a firebox arch, said superheater comprising a tortuous steam conduit, the c0nvolutions thereof being disposed in a plane making an angle with the rear tube sheet, the lower edge of the arch being closely adjacent the rear tube sheet and the lateral edges adjacent the side walls of the firebox, and steam inlet and outlet conduits for said unit passing through certain of said tubes and secured to the boiler structure in advance of said forward tube sheet, said conduits providing means for supporting the superheater unit.

12. A locomotive boiler construction comcured to the prisin a boiler shell having a firebox, spaced tube eets disposed transversel of the shell and tubes for products of combustion passing threugh the said sheets and intermediate water sp'aee lsuperheater positioned in the firebox and designed and constructed to likewise constitute a firebox arch, said su rheater comprising a tortuous steam con uit,

the convolutions thereof being disposed in a plane making an angle with the rear tube sheet, the lower edge of the arch being closely adjacent the rear tube sheet and the lateral edges ad'acent the side walls of the firebox, steam inlet and outlet conduits for said unit passing throu h oiler structure in advance of said forward tube sheet, and means associated with said lower edge of the arch and the rear tube sheet, said last named means and said steam conduits providing the sole means for supporting said superheater unit.

13. A locomotive boiler construction comprisin a boiler shell having a firebox, spaced tube s eets disposed transversely of the shell and tubes for the products of combustion passing through said sheets and the intermediate water space, two of said tubes being of relatively large diameter and positioned toward the top of said tube sheets, a superheater positioned in the firebox and designed and constructed to likewise constitute a fire box arch, said superheater com rising a tor-' tuous steam conduit, the convo utions thereof being disposed in a plane making an angle with the rear tube sheet, the lower edge of the arch thus formed being closely adjacent the rear tube sheet and supported therefrom at a centrally located point, steam inlet and outlet conduits connected with said superheater unit at the upper portion thereof and each adapted to pass through one of said enlarged fire tubes, said conduits being connected with the boiler structure in advance of the forward tube sheet, a throttle valve disposed in the steam line beyond said outlet conduit of the superheater, and a safety valve disposed in advance of said throttle va ve.

14. A locomotive boiler construction com;

certainof said tubes and seprising a boiler shell having a firebox, spaced tube sheets disposed transversely of the shell and tubes for products of combustion passing through the said sheets and intermediate water space, and a superheater positioned in the firebox and designed and constructed to likewise constitute a firebox arch, said superheater, for this purpose, comprising a tortuous steam conduit, the convolutions thereof being disposed approximately in the same plane so as to form a bafiie for the combustion gases, which extends from the lower forward portion of the firebox upwardly and rearwardly thereof and having its lateral edges adjacent the side walls of the firebox.

15. A locomotive boiler construction comprising a boiler shell having a firebox, spaced tube sheets extending transversely thereof and tubes for products of combustion passing through said sheets and intermediate water space, a combinedsuperheater and firebridge unit disposed within said firebox, and means in said firebox for supporting said unit so as to permit a slight rocking movement resulting from the expansion and contraction of the metal of which said unit, said boiler, and their associated parts are composed, whereby strain or ru ture may be prevented.

16. A locomotive prising a boiler shell having a firebox,'spaced tube sheets extending transversely thereof and tubes for products of combustion passing iler construction coma through said sheets and intermediate water parts. JOHN A. MCGREW. 

